There is no overlap between 09:00–18:00 working days in these two places.
How many hours is MST behind GST?
As abbreviations, GST is always 11 hours ahead of MST: MST is UTC−7 and GST is UTC+4. To convert, add 11 hours.
When the MST to GST time difference changes
For most of the year GST is 10 hours ahead of MST. From 1 November to 31 December 2026, GST is 11 hours ahead of MST instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
Dates
GST vs MST
Length
1 November 2026 to 31 December 2026
11 hours ahead
61 days
1 January 2027 to 13 March 2027
11 hours ahead
72 days
14 March 2027 to 6 November 2027
10 hours ahead
238 days
7 November 2027 to 31 December 2027
11 hours ahead
55 days
Calling hours for MST and GST
When GST is 10 hours ahead of MST: no shared 09:00 to 17:00 hours; try 07:00 in MST (17:00 in GST).
When GST is 11 hours ahead of MST: no shared 09:00 to 17:00 hours; try 07:00 in MST (18:00 in GST).
Frequently asked questions about MST and GST time
How many hours ahead is GST of MST?
GST (UTC+4) is 11 hours ahead of MST (UTC−7).
Does the time difference between MST and GST change?
Yes. It is usually 10 hours ahead, but changes when one side moves its clocks: 11 hours ahead from 1 November to 31 December 2026; 11 hours ahead from 1 January to 13 March 2027.